EP1876005A1 - Injection mould with lamellar elements - Google Patents

Abstract

The mold for injection molding of mascara brushes (7) for liquids, paintable or fine particle shaped materials, comprises four composite partial mold inserts (1, 2). Two of the mold inserts in each case have a carrier (3, 4) running in an axial direction and twenty lamella elements (5, 6) running in the carrier. The lamella elements of both partial mold inserts while composing both partial mold inserts in the axial direction are arranged on each other sequentially. The lamella elements with the carriers of the respective mold inserts are formed a single component. The mold for injection molding of mascara brushes (7) for liquids, paintable or fine particle shaped materials, comprises four composite partial mold inserts (1, 2). Two of the mold inserts in each case have a carrier (3, 4) running in an axial direction and twenty lamella elements (5, 6) running in the carrier. The lamella elements of both partial mold inserts while composing both partial mold inserts in the axial direction are arranged on each other sequentially and the lamella elements at the same time in the axial direction with regard to the affiliation alternate twice periodically to the both partial mold inserts. Half of the lamella elements are identical among themselves. The lamella elements two-dimensionally contact in pairs. The injection mold is so selected that the two partial mold inserts when demolding the partial mold inserts as injection mold part remain easily relative to each other and are connected with each other. Independent claims are included for: (1) an injection molding machine with an injection mold; and (2) a procedure for assembling a injection mold.

Description

The present invention relates to the technical field of injection molding.

Injection molding has long been known and widely used as a technical method for molding thermoplastic materials. A thermoplastic mass is heated so that it has sufficient fluidity, and then injected under pressure, for example via a screw, injected into an injection mold. In the injection mold, the material cools and solidifies, so that it can be removed after opening the injection mold as the mold corresponding injection molded product.

In general, injection-molded parts are relatively cheap to produce in large quantities, because the injection molding process is relatively simple and thus inexpensive to perform in itself. However, the production of the injection mold, especially for complex part geometries, is complex and expensive, so that it puts a significant burden on the costs, especially with limited quantities. The complexity of the part geometry relates, on the one hand, to the geometrical detailing of the shape and, on the other hand, also to the process of opening the mold for removal of the injection-molded product, that is to say demoulding. In this case, with regard to undercuts and the limited elasticity of the corresponding undercut product parts a corresponding division of the shape must be made.

The object of the present invention is to specify an injection mold improved with regard to sophisticated part geometries, as well as to specify a corresponding method for assembling the injection mold, for injection molding itself and a corresponding injection molding machine.

The invention is directed to an injection mold which has at least three composite mold inserts, characterized in that at least two of the mold inserts each have a carrier running in an axial direction and on the carrier a plurality of lamellar elements, the lamellar elements the two mold inserts are successively arranged in the axial direction when the two mold inserts are assembled and the laminating elements alternate in the axial direction with respect to the two mold inserts, as well as an injection molding machine having such an injection mold, a method of assembling the injection mold and a method for injection molding with this injection mold.

The basic idea of the invention is not only to divide the injection mold, as known per se, into at least three partial mold inserts which are assembled during assembly of the injection mold, but to equip at least two of these partial mold inserts with a plurality of laminar elements attached to a common carrier of the partial mold insert are held. The lamellar elements are arranged successively in the assembled state of the injection mold, wherein the direction of this sequence is referred to here as the axial direction, without any statement about the symmetry properties of this axis or a particular length of the injection mold or the mold inserts is to be connected in the direction of this axis. The axial direction should be defined only by the succession of the lamellar elements. Furthermore, the lamellar elements should alternate in this axial direction with respect to their respective affiliation with the two partial mold inserts. It should therefore belong in the axial direction directly successive lamellar elements to each different partial mold inserts.

As the exemplary embodiment illustrates figuratively, can be achieved by the division into the lamellar elements and their alternating sequence that relatively fine structures of the trainee form, so the negative mold for the injection molded product, are initially constructed in the production of the injection mold separate parts, for example, the in the axial direction, the front and rear walls of a certain part of the negative mold each belong to different fin elements. Thus, the individual fine structures need not be worked out in their fineness from the solid, such as by spark erosion, but can be introduced by editing a surface in depth. If correspondingly deepened surfaces then when assembling the part mold inserts are placed together, very fine structures can be included between the recessed surface parts.

On the other hand, a division into lamellar elements, which would then have to be handled separately, would entail a considerable complication in the assembly of the injection mold. According to the invention, instead, the lamellar elements are each assigned in groups to a carrier, so that a carrier together with the lamella elements held on it forms a total of significantly less partial mold inserts in relation to the number of lamella elements. When assembling and disassembling the injection mold, during maintenance and also during production, significantly fewer separate parts must be handled and manipulated.

The invention can be thus virtually illustrated so that the lamellar elements in the manner of comb teeth interlock when the part mold inserts are assembled, and the carrier to a certain extent correspond to the comb back. It is not absolutely necessary, but preferred that the lamellar elements periodically alternate with regard to their respective affiliation with the partial mold inserts or carriers. The order can change. It is also not absolutely necessary that next adjacent lamellar elements always and without exception belong to different partial mold inserts. Rather, there may be exceptions in this case, for example, if corresponding cavities between two lamellar elements of a partial mold insert can be limited by this and the adjacent carrier, without taking into account particularly fine structures.

Of course, more than one carrier element can emerge along the entire injection mold in the axial direction, that is to say a plurality of partial mold inserts can also be placed behind one another in the axial direction. Incidentally, in the dimensions transverse to the axial direction, according to the invention, at least three, but in most cases more than three, partial mold inserts are present "next to one another". At least two of the partial mold inserts in this case have lamella elements according to the invention, but in the case of four or more partial mold inserts, more than two partial mold inserts are preferably also provided with lamellar elements. In particular For example, the lamellar elements may be provided in pairs on the partial mold inserts, for instance on four partial mold inserts, and arranged successively in the corresponding pairing in the assembled state. In addition, even the sipe elements of more than two part mold inserts may be sequentially arranged in the assembled state of the injection mold. However, the lamellar elements of the partial mold inserts need not all be nested together, but may for example also be nested in pairs or in other group assignments and also only for a pair or a group of partial mold inserts. The invention also relates expressly to injection molds in which only part of the existing part mold inserts according to the invention have interlaced lamellar elements.

The invention is suitable not only, but particularly well for repetitive structures of the negative mold or the injection-molded product, so that it is preferred that the lamellar elements of a mold insert with each other at least to a substantial extent, approximately at least half, are identical in shape. For the sake of illustration, reference is made to the exemplary embodiment. Repetitive structures can also be present if the lamellar elements only clearly resemble each other along the axial direction, but are not really identical, for example in the case of structures with a "curved silhouette" of otherwise identical individual elements.

A preferred and particularly simple embodiment of the invention provides that the lamellar elements of the two or two partial mold inserts in each case alternate with one another, ie alternate twice. This does not exclude that, in particular transversely to the axis, there are not also further part-mold inserts with further lamellar elements which, however, do not participate in the alternating sequence of the previously described lamellar elements of the two part-mold inserts. For the sake of illustration, reference is again made to the exemplary embodiment.

Furthermore, it is preferably provided that in each case next adjacent lamellar elements (in pairs) touch flat, so come into contact with each other over a part of their surface with which they face each other, which defines a portion of the negative mold for the injection molded product in this part. In the remaining Part of the surfaces they are correspondingly deepened and thus define a proportion of the negative form.

It is particularly preferred that at least a portion of the interleaved arrangements of the lamellar elements is maintained during operation of the injection mold, so the two mold inserts with the lamella elements or pairs of such mold inserts remain in relative rest position to each other when a demolding takes place, so injection moldings are separated from each other after an injection molding process to remove an injection molded product. Here, therefore, the division according to the invention in partial mold inserts and lamellar elements has the meaning of simpler production and easier assembly of injection moldings and nothing to do with the separation processes during demoulding. For example, an injection mold may have two injection mold halves, each consisting of a partial mold insert pair, or may have injection mold quarter each of a pair of mold inserts. Embodiments of the invention may also be advantageous in which some lamellar elements are separated from each other during removal, and others remain in rest position relative to each other, the division according to the invention into lamellar elements partly relates to the structure of injection moldings stationary during the removal processes and partly also to the geometric structure in the context of this meshing and separation concern the interlocking when closing the injection mold and separated from each other during demolding injection molded parts.

In the most general sense of the invention, at least two partial mold inserts with respective slat elements are provided (which preferably remain connected during demoulding) and a third partial mold insert, which need not have any slat elements and is separated from the other two partial mold inserts during demolding.

Furthermore, the lamellar elements are preferably formed integrally with the respective carriers, ie in each case produced in a block with the carriers. Alternatively, but less preferably, a layer by layer, about lamella element-wise production and subsequent connection in the axial direction is possible.

The invention is particularly suitable for the injection molding of products which have a complex shape in so far as they form a surface configured to receive or adhere substances. The invention is thus directed, inter alia. preferred to the production of applicators of various kinds, so forms with relatively complex and compared to the size of the applicator large surface, which absorb by adhering liquid, spreadable or fine particulate materials and apply these to a specific location or surface. In the narrower sense, these may be brushes, ie structures with a multiplicity of juxtaposed bristles, also in the form of protrusions or knobs that taper or otherwise form. Also suitable as applicators are structures in the geometric type of conventional honey applicators, ie parallel lamellae or discs held on a stem. The applicator structures in the most interesting case are much smaller than known from honey applicators. Incidentally, of course, the Applikatorenköpfen the speech, which may be provided with handles or stems, but need not.

When it comes to taking up substances by adhering to a surface for removal from a particular location or surface, one can also speak of brushes or, in the case of generalized geometries, similar to the described honey spoon, also of brushes in a more general sense. This more general sense of "brush" should also apply to the application described above.

A very particularly preferred embodiment of the invention is intended for the production of very small plastic brushes or applicators for applying cosmetic products, in particular mascara brushes. This is particularly filigree and numerous structures, because the cosmetic brush is very small overall, about to be handled safely on the eye, and to be able to record a very fine bound material.

Other preferred applications are filters and absorbers for the separation of substances from a fluid medium, vibration dampers, mixers, ie structures that serve to mix substances by movement therein, in chemical reactors, etc.

In these and other applications, cases are preferred in which the "complexity" of the shape to be produced is relatively large, which may be u. a. in a relatively large number of fin elements. Preferably, the total number of lamella elements, that is to say including all partial mold inserts involved, is at least 20, wherein preferably at least 10 are dispensed with each partial mold insert. However, the invention is also advantageous and reasonably executable, if the number of lamellar elements is significantly smaller, for example, only between 3 and 10 per support beam.

The invention thus allows a relatively simple and efficient construction of the injection mold, which is expressed both in their device properties and in their production. Finally, this also improves the injection molding machine and the injection molding process, because their performance is largely determined by the properties of the injection mold.

Figur 1

zeigt eine perspektivische Ansicht eines Teils einer erfindungsgemäßen Spritzgussform in Gestalt zweier Ausschnitte aus Teilformeinsätzen mit Lamellenelementen in getrenntem Zustand zusammen mit einem entsprechenden Teil eines zugehörigen Spritzgussprodukts.

Figur 2

zeigt die Ausschnitte aus den Teilformeinsätzen aus Figur 1 zusammen mit dem Teil des Spritzgussprodukts in zusammengefügtem Zustand, und zwar wiederum in perspektivischer Ansicht.

Figur 3

zeigt eine Draufsicht und drei Seitenansichten zu Figur 2.

In the following, an embodiment of the invention is explained in more detail with reference to the figures, wherein the individual features may be essential to the invention in other combinations and the disclosure, as well as the above description, implicitly refers to all device and process categories of the invention.

FIG. 1

shows a perspective view of a portion of an injection mold according to the invention in the form of two sections of part mold inserts with lamellar elements in a separate state together with a corresponding part of an associated injection molded product.

FIG. 2

shows the cutouts from the part mold inserts of Figure 1 together with the part of the injection molded product in the assembled state, again in a perspective view.

FIG. 3

shows a plan view and three side views of Figure 2.

In Figure 1 can be seen two partial mold inserts 1 and 2, the respective carrier 3 and 4 in the form of substantially rectangular bars have. At the cuboidal supports 3 and 4 respectively slat elements 5 and 6 are mounted, which are connected in one piece with the carriers 3 and 4 in the present case. Of course, they could also be manufactured separately within the scope of the invention and subsequently attached to the carrier. The basic geometry of the lamellar elements 5 and 6 is that of a right-angled triangle, wherein the peak assigned to the right angle is cut away in each case by a circular cutout with the center in this point and the lamellar elements 5 and 6 in the axial direction, here from the front right to the rear left, so to speak a parallel displacement of the triangle in the axial direction corresponding basic shape.

The figures also show that between the respective mutually facing sides of the lamellar elements 5 and 6 of the cutaway tip (at the right angle of the right triangle) emanating part of a star shape with which the triangular side surfaces are recessed. In this case, the front plate member 5 of the left part insert 3 is excluded with its forward facing side surface.

As shown in FIG. 1, the part mold inserts 1 and 2 can simply be pushed together, with the lamella elements 5 and 6 interleaving in the manner of a comb tine, resulting in a structure as in FIG. 2 and FIG. In this case, the carrier 3 and 4 abut each other. The star-shaped cutouts thereby form relatively fine hollow molds for the injection mold product 7 drawn separately in FIG. 1 above the partial mold inserts 1 and 2 and in the negative mold in FIGS. 2 and 3. This injection molded product is a part of a mascara brush with it outwards each tapering individual bristles, which effectively form the rays of the star shape. Three of these bristles are detected by the two part mold inserts 3 and 4, namely the three lower, with the outer one of these three only in each case half. If you think in Figure 2, another three Teilformeinsatzpaare each rotated by 90 ° to the axis defined by the center axis of the mascara brush 7 axis, there is a complete negative mold for the mascara brush 7. The circular cutouts at the vertices of the triangle at right angles correspond to the axially and centrally located cylinder of the mascara brush 7.

It can be seen that the partial mold inserts 1 and 2 and also the remaining three partial mold insert pairs remain in pairs during removal from the mold, that is to say when removing the mascara brush 7. The partial mold inserts of the pairs are thus assembled in pairs only during assembly of the injection mold and put together during operation. When demoulding, alternatively, two partial mold insert pairs on the one hand, ie an injection mold half, and two other partial mold insert pairs on the other hand, ie a further injection mold half, can be separated from each other, or also injection mold quarters can be separated from each other, if this simplifies the demoulding process.

It can also be clearly seen that the approximately triangular side surfaces of the lamellar elements 5 and 6 can be machined by deepening, without the size of the dimensions corresponding to the thickness of the star shapes of the finished mascara brush 7 (in the axial direction) being fully recognized as a problem , Namely, the negative forms for these stars do not have to be worked out of the solid, but can be much easier to produce by virtue of the fact that each of the lamella elements 6 of the other part-form insert between two lamella elements 5 is missing (or vice versa). It can further be seen that here the lamellar elements in the region of the illustrated section from the entire mascara brush, which has approximately thirty to forty instead of the nine repeating star structures shown here, are identical to one another. This applies with the exception of the visible front surface of the foremost lamellar element 5 of the part mold insert 1 and the rear front surface of the rearmost lamellar element 6 of the part mold insert 2. Furthermore, the lamellar elements alternate in the axial direction twice and extent periodically. If there were three or more partial form inserts participating in the alternating series, then also periodic orders would be preferred.

Claims (16)

injection mold
which has at least three composite part mold inserts (1, 2),
characterized in that
at least two of the partial mold inserts (1, 2) each have a carrier (3, 4) running in an axial direction and on the carrier (3, 4) a plurality of laminar elements (5, 6),
the lamellar elements (5, 6) of the two part-mold inserts (1, 2) are arranged successively in the axial direction during the assembly of the two part-mold inserts (1, 2)
and the lamellar elements (5, 6) alternate in the axial direction with respect to the affiliation with the two partial mold inserts (1, 2). An injection mold according to claim 1, wherein the fin elements (5, 6) periodically alternate in the axial direction. Injection mold according to claim 1 or 2, wherein at least half of the lamellar elements (5, 6) of each of the two mold inserts (1, 2) are identical in shape to each other. Injection mold according to one of the preceding claims, in which the lamellar elements (5, 6) alternate in each case twice. Injection mold according to one of the preceding claims, in which the lamellar elements (5, 6) of the two part-mold inserts (1, 2) touch each other in pairs in a planar manner. Injection mold according to one of the preceding claims, comprising at least four composite part mold inserts (1, 2) each having a carrier (3, 4) running in the axial direction and a plurality of plate elements (5, 6) on the carrier (3, 4). have, wherein the lamellar elements (5, 6) respectively two of the part mold inserts (1, 2) are arranged successively in the axial direction in the assembly of the part mold inserts and the lamellar elements (5, 6) alternate in the axial direction with respect to the affiliation to the respective two part mold inserts. Injection mold according to one of the preceding claims, which is designed so that the two part mold inserts (1, 2), the lamellar elements (5, 6) are arranged successively in the axial direction, remain arranged successively during demolding and the two associated part mold inserts ( 1, 2) when demoulding as injection molded part relative to each other at rest and stay connected. Injection mold according to one of the preceding claims, in which the lamellar elements (5, 6) are integrally formed with the carriers (3, 4) of the respective part-mold inserts (1, 2). Injection mold according to one of the preceding claims, which is designed for injection molding of an applicator (7) for liquid, spreadable or fine particulate material. Injection mold according to one of the preceding claims, which is designed for injection molding a brush (7). Injection mold according to Claims 9 and 10, in which the injection-molded product (7) is a cosmetic brush, in particular a mascara brush. Injection mold according to one of the preceding claims, in which the number of lamellar elements (5, 6) is at least twenty. Injection molding machine with an injection mold according to one of the preceding claims. A method of assembling an injection mold according to any one of claims 1 to 12,
in which at least three partial mold inserts (1, 2) are assembled,
characterized in that
at least two of the partial mold inserts (1, 2) each have a carrier (3, 4) running in an axial direction and on the carrier (3, 4) a plurality of laminar elements (5, 6),
the lamellar elements (5, 6) of the two partial mold inserts (1, 2) are arranged successively in the axial direction during the assembly of the two partial mold inserts (1, 2)
and the lamellar elements (5, 6) alternate in the axial direction with respect to the affiliation with the two partial mold inserts (1, 2). Method for injection molding, in which an injection mold according to one of claims 1 to 12 prepared and injection molding compound is injected into the injection mold for producing an injection molded product (7). The method of claim 15, wherein the injection mold is assembled prior to injection molding, wherein the part mold inserts (1, 2) are assembled.

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